The motional behavior of complex phthalates and structurally related liquids has been investigated in order to study the structural effect of molecular framework on the macroscopic and microscopic dynamic properties. C-13 NMR spin-lattice relaxation times and nuclear Overhauser enhancements (NOE) of individual carbon nuclei of bis(2-ethylhexyl) cyclohexane-1,2-dicarboxylate (DEHHP), bis(2-ethylhexyl) isophthalate (DEHIP), bis(2-ethylhexyl) terephthalate (DEHTP), and tris(2-ethylhexyl) trimellitate (TOTM) have been measured as a function of temperature from -40 to 90 degrees C. Individual C-13 peaks were unambiguously assigned by using 2D hydrogen-carbon chemical shift correlation spectra. In addition, the density and viscosity of these compounds as a function of temperature have been measured. The results were also compared with those of 2-ethylhexyl benzoate (EHB), 2-ethylhexyl cyclohexanecarboxylate (EHC), and bis(2-ethylhexyl) phthalate (DEHP), complex liquids studied earlier in our laboratory. Both the macroscopic and microscopic dynamic properties were significantly affected by the structure of the molecular framework. The conjugation between a phenyl ring and carboxyl groups was found to make the structural framework stiffer and resulted in an enhanced viscosity. The C-13 NMR relaxation data were interpreted in terms of a theoretical model assuming a Cole-Davidson distribution of correlation times. The internal motions of the common 2-ethylhexyl side chains were found to be independent of the nature of the molecular framework of the compounds. The parameter beta in the Cole-Davidson model, representing the distribution width of the involved correlation times of the molecular motions, contained useful information on the detailed motional features of individual carbon nuclei. The beta values for the rigid phenyl ring carbons reflected the reorientational anisotropy resulting from the molecular shape of the structural framework and could be successfully correlated with the parameter kappa introduced by McClung and Kivelson in the modified Stokes-Einstein-Debye (SED) equation. On the other hand, the beta values for the flexible cyclohexane ring carbons were affected by both the internal motion of the cyclohexane ring and the anisotropy of the molecular reorientation.